A large number of persons suffer wounds of the type in which healing of the damaged tissue is limited by the amount of oxygen in the air normally exposed to the wound. Burns are the primary example and healing of damaged tissue characteristic of burns can be accelerated by increasing the amount of oxygen at the damaged tissue. Oxygen tents surrounding the entire victim or the burn area (hyperbaric chambers) have been used but not overly successfully because they present safety problems, the exchange rate of the oxygen and damaged tissue is not remarkably better, and they do not always eliminate bacterial infections which are prone to occur during the healing period.
The healing of many other types of wounds is subject to increased healing rate if the amount of oxygen exposed to the viable cells in and around the damaged tissue area is increased. These include such relatively minor wounds as ordinary cuts but also extend to surgical incisions, gunshot wounds, knife wounds, the skin opening left by the surgical removal of warts, bedsores (a form of ulcers), bone fractures where the broken bone penetrates the skin, the various cuts and injuries associated with automobile and other accidents, and the like. Most common such wounds are on the skin surface such as the arms, legs, roof of the mouth, etc., i.e., the body areas readily exposed to the atmosphere, but other areas such as the stomach, bones, lungs and the like can suffer similar type wounds, such as stomach ulcers, the actual break area in a broken bone, etc., where lack of oxygen slows down the healing rate.
The wounds described above all involve a discontinuity in the body tissue. It is this discontinuity, as in a cut finger, which needs to heal and the regeneration of the damaged or destroyed tissue is proportional to oxygen availability. The wounds described above do not encompass ordinary bruises where the problem is solely broken blood vessels resulting in black and blue marks but not in any tissue discontinuity.
Of the wounds described above burns are on the whole the most serious type. They often cover in the aggregate a larger area of the body but even individual burn areas are usually larger than the areas of the other wounds mentioned. Consequently they deserve special mention.
A large number of humans are burned each year, for example, one article "Burn Wound Coverings--A Review", by G. B. Park, appearing in Biomater. Med. Devices, Artif. Organs 6(1), 1-35, 1978 states that in the U.S. more than 2 million persons are burned seriously enough each year to need medical attention. It further states that some 70,000 persons each year require hospitalization, with 10,000 persons dying as a result of their injury.
The type of treatment for a burn is determined by the degree of the burn and the amount of surface area affected. With a serious burn one mode of treatment involves debridement, i.e., the removal of burned tissue by means involving e.g., surgery, mechanical or biochemical means. The latter is illustrated by enzymatic debridement using an enzymatic debriding agent which is usually applied in the form of an ointment. These agents are proteolytic enzymes that will selectively digest necrotic tissue without harming adjacent viable tissue. Other debridement techniques include the use of a tank filled with plain tap water maintained at a suitable temperature and strict sterile conditions. Once the human is in the tank, any dressings are removed and the burn cleaned and debrided. Afterwards the human is removed and covered with a sterile sheet and transferred to an adjacent dressing room of proper temperature and humidity.
Removal of the burned tissue can cause certain problems. Human skin, in addition to being an effective barrier against harmful external materials, prevents the body from losing its water. Such water loss, according to the article by Park, can cause intense catabolism which "manifests itself as increased heat production, increased water loss and nitrogen consumption, weight loss, negative nitrogen balance and loss of other cellular constituents derived largely from muscle." Intense catabolism can be fatal, and thus should be minimized or controlled.
Another problem, again according to the article by Park, is that "the preparation of a clean viable tissue area suitable for grafting is all-important and many lives may be lost by not securing a good take of a first graft in an extensively burned patient."
Articles which describe in greater detail the foregoing treatment and problems include the following: "Burn Injuries, Initial Evaluation and Treatment" Luterman, CUTIS 22(4):437-42, October 78; Care of the Burn Wound, Yarborough, M. F., CUTIS 22(4):447-52, October 78; Advances in Fluid Therapy and the Early Care of the Burn Patient, Pruitt, B. S. Jr., World J. Surg. 2(2):139-50, March 78; Emergency Burn Management, Gursel, E. et al. JACEP 7(5):209-12, May 78.
The use of water during debridement can be less than desirable. Water can be difficult to maintain in a pure state and microorganisms can easily grow in it. Yet chemicals, such as chlorine, used to prevent such growth could adversely affect unprotected tissue. Water containing microorganisms can facilitate the invasion of the body with harmful results. Thus, the burn victim, lacking his normal skin barrier, can be infected by the water contacting his unprotected tissue. Further, the water could adversely affect the preparation of a clean viable tissue area suitable for grafting by extracting helpful components from the contacted tissue.
While much of the foregoing discussion is expressed as a treatment of a human, no such limitation is intended. The wound treatments described and claimed hereinafter by the applicant are applicable to animal victims generally and not limited to humans.